Lecture 1:
SCIENTIFIC METHOD constitute data (example- movie ratings) STATISTICS: a
science of drawing conclusions from data (EXAMPLE- mean=3.3/4 stars) CATIGORICAL
VARIABLES: Social Class, Political Party, Population density, religion QUANTITATIVE VARIAB
Lecture 5: DESCRIPTIVE STATS organizes and summarizes the available data in a
meaningful way (You know everything about the data). Statistical tools/procedures to help
organize, summarize, and simplify a large set of data. INFERENTIAL STATS infers populat
Lecture 10: Distribution of Sample Means-is the collection of sample means for all the possible random samples of a particular size that can
be obtained from a population. The distribution of sample means is a population distribution. Central Limit Theor
Q1
Based on a sample of 50 x-values having mean 35.36 and standard deviation 4.26,
(a)
test at the 0.05 level of significance the null hypothesis : = 34 versus the alternative : 34.
(b)
find a 95% confidence interval for the population mean.
(c)
determine
Q1
A.
To find P(a < Z < b) = F(b) - F(a)
P(X < 0.03) = (0.03-0)/1
= 0.03/1 = 0.03
= P ( Z <0.03) From Standard Normal Table
= 0.51197
P(X < 1.01) = (1.01-0)/1
= 1.01/1 = 1.01
= P ( Z <1.01) From Standard Normal Table
= 0.84375
P(0.03 < X < 1.01) = 0.84375
East Brunswick High school has 1600 students. A sample of 160 students was selected to study
the average monthly income of students. Since sample size is greater than 30, how much error
would you expect in finding the average income of all students?
a) 5
Q1
A population has = 80 and = 12. Find the z statistic corresponding M = 84 for a sample if n = 5. MY ANSWER: I got z = .75. Is this correct?
Ans.
Test Used: Z-Test For Single Mean
Set Up Hypothesis
Null Hypothesis H0: U=80
Alternate Hypothesis H1: U!=80
Q1
Ans.
A.
i.
Mean = Sum of the observations / No.of the observations
Here n = 20 ; Sum of the observations = 127
Mean = 127/20 = 6.35
ii.
Median is the middle observation. If N is odd, use the formula (N+1)/2 th observation. If it is even use the formula
Q1
Explaining confidence. A student reads that a 95% confidence interval for the mean ideal weight given by adult American women is 140 1.4 pounds. Asked
to explain the meaning of this interval, the student says, 95% of all adult American women would say
When calculating the standard deviation and variance from a sample, which of the following is the
denominator for the biased estimate of the population standard deviation and the biased estimate
of the population variance? ( Point)
N
N1
N+1
N2
N+2
Answer)
Please show all work. Include formulas, calculations, or definitions necessary to solve the problems. I recommend that you use Excel. You may also use Word, but must attach the Excel
workbook used for calculations or paste the work in the document. Feel f
Q1
The conductivity of fibrous-glass board. How well materials conduct heat matters when designing houses, for example. Conductivity is measured
in terms of watts of heat power transmitted per square meter of surface per degree Celsius of temperature diff
Q1
Sixty percent of patients undergoing a certain hospital procedure are expected to require an overnight stay. The hospital schedules 8 patients for this
procedure each day. They set aside 6 beds to accommodate expected overnight stays for these patients
Data from Table Splitting for each year
Excelformulas
ForSum:
SUMIFS(B2:B2151,C2:C2151,"2002")
SUMIFS(B2:B2151,C2:C2151,"2003")
Likewise till SUMIFS(B2:B2151,C2:C2151,"2011")
ForCount :
COUNTIF($C$2:$C$2151,"2002")
COUNTIF($C$2:$C$2151,"2003")
Likewise t
Q1
Some insurance companies claim that the rate of serious and fatal accidents is higher when the car size is smaller, and therefore question the policy of
offering reduced rates to owners of small cars. To investigate this, a researcher analysed a sample
Q1
For the following set of data, find the range and the interquartile range. Label each answer
with the appropriate term. Scores: 3, 2, 6, 4, 5, 3, 1, 6
ANS
Range = Maximum Minimum
Maximum value in list = 6
Minimum value in list = 1
Range = Maximum Minim
Q1
1.) A radio station that plays classical music has a "by request" PROGRAM each Saturday evening. The percentages of requests for composers on a
particular night are as
follows.
Bach
19%
Beethoven
12%
Brahms
8%
Dvorak
3%
Mendelssohn
7%
Mozart
17%
Schube
Question#24,Chapter2
The following frequency distribution presents a set of exam scores for a class of N = 20 students.
x
90-99
80-89
70-79
60-69
50-59
f
4
7
4
3
2
a.
b.
c.
d.
cf
20
16
9
5
2
C%
100
80
45
25
10
find the 30th percentile.
Find the 88th perce
Q1.
The average thickness of books on a library shelf is 8.3 centimeters. The standard deviation is 0.6 centimeter. If 20% of the books are oversized, find the
minimum thickness of the oversized books on the library shelf. Assume the variable is normally
Q1
Last month, the mean and standard deviation of the pay checks of 10 employees of a small
company were $1250 and $150, respectively. This month, each one of the 10 employees received a 10% raise on his/her pay check. What is the mean and
standard deviat
Q1
No error is committed when the null hypothesis is rejected when it is false
A. True, reason definition of TYPE I error gives reject Ho when It is true, it works when error is committed and for no error it is false
Q3
The test value separates the critic
Q1.
For a normal distribution curve with a mean of 19 and a standard deviation of 6, which range of the variable defines an area under the curve corresponding to
a probability of approximately 68%?
Ans
Normal Distribution
Mean ( u ) =19
Standard Deviation
Q1
A school board is evaluating a learning system designed to increase literacy skills. A standardized test measuring reading skills is performed on some
students, both before and after using the learning system. The following data were obtained:
student